{
\def\sym#1{\ifmmode^{#1}\else\(^{#1}\)\fi}
\begin{tabular}{l*{6}{c}}
\hline\hline
          &\multicolumn{1}{c}{(1)}         &\multicolumn{1}{c}{(2)}         &\multicolumn{1}{c}{(3)}         &\multicolumn{1}{c}{(4)}         &\multicolumn{1}{c}{(5)}         &\multicolumn{1}{c}{(6)}         \\
\hline
ST        &   -0.107         &   -0.185\sym{*}  &   -0.148\sym{**} &   -0.225\sym{*}  &   -0.011         &   -0.017         \\
          &  (0.073)         &  (0.106)         &  (0.072)         &  (0.125)         &  (0.134)         &  (0.153)         \\
\hline
\(N\)     &    14965         &    16662         &    10168         &     8948         &     4838         &     5305         \\
\(R^{2}\) &    0.052         &    0.049         &    0.066         &    0.057         &    0.053         &    0.055         \\
\hline\hline
\end{tabular}
}
